Messages in this thread |  | | From | Jim Cromie <> | Subject | [PATCH v2 00/24] dynamic_debug cleanups, query features, WIP print-classes | Date | Sat, 13 Jun 2020 09:57:14 -0600 |
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Patchset starts with 9 "cleanups"; - change section name from vague "__verbose" to "__dyndbg" - cleaner docs, drop obsolete comment & useless debug prints, refine verbosity, fix a BUG_ON, ram reporting miscounts.
It adds a few query parsing conveniences; accept combined file:line & file:func forms
file inode.c:100-200 # file & line-range file inode.c:start_* # file & function
Then it expands flags:
Adds 'u' user flag, allowing user to compose an arbitrary set of callsites by marking them with 'u', without altering current print-modifying flags.
Adds 'PFMLTU' flags, which negate their lower-case counterparts.
Adds filter-flags, which select callsites for modification based upon their current flags. This lets user activate the set of callsites marked with 'u' in a batch.
echo 'u+p' > control
By using negating-flags in your filter, you can match on an exact flagstate; not just required flags, but prohibited ones.
So if youre using dyndbg to track 2 separate problems, you can use different patterns of [fmltu] flags to keep the 2 sets of pr-debug activations separate.
By also using negating-flags in your modflags (after the [+-=] op) you can fully control the new flagstate, or modify any part of it (unlike if =p is used).
Also, a late addition: parse args like: file=afile:afunc module:kvm* I tried to drag this up to cleanups, but has a conflict so I punted.
WIP print-classes (new from previous)
cc: <stanimir.varbanov@linaro.org>
A patchset from Stanimir tried to create mutually exclusive HI, MID, LO print-classes for his module, which drove some discussion. These patches implement a working scheme:
The whole macro stack in dynamic_debug.h is adapted to *_cl() versions, and old names are redefined to use the new *_cl names, with a default print-class=0.
pr_debug_n(pr_class>0) provides a way to "create" HI MID LO classes, by just claiming an N>0. print-classes are meant to be module-scoped; so manual allocation of them in module #defines is practical.
"mflags <print-classes>" the query term is implemented, crudely but functional.
To partly enforce print-class locality to a module, "module foo" is required if "mflags flags" is used; but this can be defeated by "module *". Its easy to error out if '*' is used in query, but maybe "module kvm*" should work, as kvm* developers could probably reach agreement on print-class constants
Use of above is demonstrated in a patch to samples/kobject/kset-example
I hope this WIP doesnt distract from the non-WIP stuff.
Previous submission (in this release cycle) https://lkml.org/lkml/2020/6/5/766 changes since: WIP print-classes rebase over a recent conflict in master 2 more "cleanups": Docs ~= s/arch_init/early_init/, maybe macro else coding style fix. thx JB commit message corrections, improvements based on comments
Jim Cromie (24):
cleanups: dyndbg-docs: eschew file /full/path query in docs dyndbg-docs: initialization is done early, not arch dyndbg: drop obsolete comment on ddebug_proc_open dyndbg: refine debug verbosity; 1 is basic, 2 more chatty dyndbg: rename __verbose section to __dyndbg dyndbg: fix overcounting of ram used by dyndbg dyndbg: fix a BUG_ON in ddebug_describe_flags dyndbg: make ddebug_tables list LIFO for add/remove_module dyndbg: add maybe(str,"") macro to reduce code
file:(func|lines) dyndbg: refactor parse_linerange out of ddebug_parse_query dyndbg: accept 'file foo.c:func1' and 'file foo.c:10-100'
internal rework dyndbg: refactor ddebug_read_flags out of ddebug_parse_flags dyndbg: combine flags & mask into a struct, use that dyndbg: add filter parameter to ddebug_parse_flags dyndbg: extend ddebug_parse_flags to accept optional filter-flags dyndbg: prefer declarative init in caller, to memset in callee
expose features dyndbg: add user-flag, negating-flags, and filtering on flags dyndbg: allow negating flag-chars in modflags
recent, not trivially backport dyndbg: accept query terms like module:foo and file=bar
WIP dyndbg: WIP towards debug-print-class based callsite controls dyndbg: adapt header macros to pass print-class dyndbg: add print-class as trailing number to control output kset-example: add pr_debug()s for easy visibility of its operation kset-example: use pr_debug_n to create example print-classes
.../admin-guide/dynamic-debug-howto.rst | 79 ++-- include/asm-generic/vmlinux.lds.h | 6 +- include/linux/dynamic_debug.h | 75 ++-- include/linux/printk.h | 5 +- kernel/module.c | 2 +- lib/dynamic_debug.c | 369 +++++++++++------- samples/kobject/kset-example.c | 32 ++ 7 files changed, 374 insertions(+), 194 deletions(-)
-- 2.26.2
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